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Exploring Charmed Particles at Belle: Decoding Z(4430) and Related Phenomena

This overview delves into the fascinating world of charmed particles, focusing on the enigmatic Z(4430) and X(3872) states within the context of the 4-quark model. Recent results from KEK provide insights into the properties and interpretations of these particles, shedding light on their potential exotic nature. The Belle experiment's meticulous observations and analysis techniques reveal intriguing details about Z(4430) and its relation to ψ'π+ and other decay modes, offering a glimpse into the complex realm of particle physics. Join us on a journey of discovery as we uncover the mysteries of these charmed entities.

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Exploring Charmed Particles at Belle: Decoding Z(4430) and Related Phenomena

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  1. Z(4430) and related results at Belle Outline • Observation of Z+(4430)→ψ’π+ in B→ψ’π+K decays • Z(4430) interpretation within 4-quark model • Recent results on X(3872) • Summary Jolanta Brodzicka (KEK) 20/11/2007 KEK

  2. Recent KEK press release Jolanta Brodzicka Z(4430) and related KEK 20/11/20072

  3. Tsukuba • Asymmetric e+e- collider • e+: 3.5 GeV  e-: 8.0 GeV • CM energy: 10.58 GeV at (4S) • e+e-  (4S)  BB • Advantages: • exclusive source of BB pairs • useful kinematical constraints • high signal-to-background ratio • separation of B decay vertices • Record luminosity peak:1.711034cm-2s-1 • Integrated luminosity: ~742 fb-1 • ~ 780 * 106 BB • Beauty Factory KEK B Factory Jolanta Brodzicka for Belle New charmed particles JPS/DPF 2006 3

  4. Aerogel Cherenkov Counter Time of Flight Counter Central Drift Chamber SC Solenoid 1.5T KL /Detector Silicon Vertex Detector Electromagnetic Calorimeter • Event reconstruction Charged tracks • Central Drift Chamber • Silicon Vertex Detector Electrons and photons • Electromagnetic Calorimeter 3.5 GeV e+ Belle Detector • Particle identification • K/ separation • Central Drift Chamber: dE/dx • Aerogel Cherenkov Counter • Time of Flight Counter • Electron identification • Electromagnetic Calorimeter KL and  identification • KL and muon detector Vertexing • Silicon Vertex Detector 8 GeV e- Jolanta Brodzicka for Belle New charmed particles JPS/DPF 2006 4

  5. Cabbibo-favored vertices b c u, dc s K(*) u, d B charmonium (-like) W Good place for spectroscopy study! Charmonium(-like) factory Following B decays used: Advantages: b→cW→ccs is Cabbibo-favored process (not rare) background reduction is possible JPof parent B is known → JPof the child particles can be determined from angular analysis Jolanta Brodzicka Z(4430) and related KEK 20/11/20075

  6. Study of B→ψ’π+K B0 →ψ’π+K- and B+→ψ’π+K0s studied using 657·106 BB data ψ’→ e+e-, μ+μ- or J/ψπ+π- J/ψ →e+e-, μ+μ- K0s→π+π- secondary particles combined to B→ψ’π+K candidates B signal identification takes advantage of Υ(4S)→BB kinematics: EB=Ebeam=√s/2in cms kinematical variables used in B factories Mbc= √E2beam- p2B beam-constrained mass (signal at mB~5.28GeV) ΔE=EB- Ebeam cms energy difference (signal peaks at 0) clear B signal seen hep-ex/0708.1790 Submitted to PRL Jolanta Brodzicka Z(4430) and related KEK 20/11/20076

  7. ??? M2(ψ’π+) K2*(1430) K*(890) M2(Kπ+) B→ψ’π+KDalitz plot Z+(4430) in addition to expected B→ψ’K* components a clear band seen at M2(ψ’π+)~20GeV2 to study ψ’π+ structure we apply K*veto (both K* regions excluded) M(ψ’π+) fitted with Breit-Wigner + phase-space like function prominent peak (K* veto applied) 3-body decays non-B background M(ψ’π+) Nsig =121 ± 30 (6.5σ) M= 4433 ± 4 MeV Γ= 45+18-13 MeV Jolanta Brodzicka Z(4430) and related KEK 20/11/20077

  8. Is Z(4430) signal robust? data subsets checked, K* veto changed → consistent Z parameters interference between different (S,P,D) Kπ partial waves → cannot produce such narrow peak in ψ’π+ B generic MC studied → Z(4430) is not a reflection interference with 3-body → does not affect Z parameters much anything else contributed besides vetoed K*’s? no conclusion: Z(4430) signal is robust M(Kπ) for Z(4430) signal region without K* veto Jolanta Brodzicka Z(4430) and related KEK 20/11/20078

  9. hep-ex/0708.1790 Submitted to PRL Z+(4430) Z+(4430) properties M(ψ’π+) we cannot determine its JP with present statistics First candidate for a charged charmonium-like state! Must be exotic! It could be a tetraquark state either diquark [cu][cd] or molecular (cd)(cu) (Charged states naturally appear within multiquark models) Jolanta Brodzicka Z(4430) and related KEK 20/11/20079

  10. u c d c Xu= Xd= u c d c Maiani, Polosa et al. PRD 71, 014028 (2005) hep-ph/0707.3354 hep-hp/0708.3997 Within 4-quark model(by Maiani, Polosa et al.) Z+(4430)→Ψ’π+ can be diquark-antidiquark state [cu][cd] charged member of JPC=1+- multiplet it can be radial excitation of lowest lying 4-quarks with JPC=1++: X0u[cu][cu] X0d[cd][cd] X(3872) is candidate for such 4-quark state (but doublet needed) Mass splitting: M(Xu ) - M(Xd) ~2(md – mu)=8 ± 3 MeV (but mixing possible) Production rates in charged B larger than in neutral B B+→K+Xu B0→K0Xd Jolanta Brodzicka Z(4430) and related KEK 20/11/200710

  11. PRL 91, 262001 (2003) Reminder on X(3872) M(J/Ψππ) X(3872)→J/Ψπ+π- observed B+→X(3872)K+ by Belle confirmed by BaBar, CDF, D0 PDG06: M=3871.2 ± 0.5MeV Γ<2.3MeV other decay modes: X(3872)→J/Ψγ, J/Ψω, DDπ favored spin-parity: 1++(by the decay modes and angular analysis by CDF/Belle) What is X(3872)? does not match any cc state predicted by quark models DD* molecule? MX-(MD*0+ MD0)= -0.6±0.6 MeV 4-quark? Would explain small width. Charged X should exist X(3872) properties still under investigation (mass, width, line shape, decay modes…) Jolanta Brodzicka Z(4430) and related KEK 20/11/2007 11

  12. BELLE-CONF-0711 New X(3872)→J/ψπ+π-results B0→XK0s Ns=30±7 (6.5σ) B+→XK+ Ns=125±14 (12σ) First observation! Motivated by 4-quark model predictions B+→X(3872)K+ and B0→X(3872)K0s X(3872)→J/ψπ+π-with 657MBB control sample: B→ψ’K ψ’→J/ψπ+ π-(to calibrate mass & resolution) look at ΔM= M(J/ψπ+ π-) - M(J/ψ)+mJ/ψ models predicting different properties for X(3872) from neutral and charged B decays are disfavored Jolanta Brodzicka Z(4430) and related KEK 20/11/200712

  13. PRL 97, 162002(2006) hep-ex/0708.1565 Surprises from X(3872)→D*D X(3872) is very close to D*0D0 mass threshold BaBar: B+→D*0D0K K=K+or K0 D*0 →D0π0,D0γ (with 383·106 BB) Belle: B+→ D0D0 π0K K=K+or K0 (with 447·106 BB) mass ~4σ away from X →J/Ψπ+π- are there two states X(3872) and X(3875)? Ns=33 ± 7 (4.9σ) M(X)=3875.1+0.7-0.5 ±0.5 MeV Γ=3.0+1.9-1.4 ± 0.9 MeV Ns=24 ± 6 (6.4σ) M(X)=3875.4 ± 0.7+0.4-1.7 ±0.9 MeV Γ=3.0+1.9-1.4 ± 0.9 MeV Jolanta Brodzicka Z(4430) and related KEK 20/11/200713

  14. Still within 4-quark model?(by Maiani, Polosa et al.) u c d c Xu= Xd= u c d c Maiani, Polosa et al. hep-ph/0707.3354 hep-hp/0708.3997 Model revised: Xustate decaying to D0D0π0 / D*0D0= X(3875) Xdstate decaying to J/Ψπ+π-= X(3872) (why Xd lighter than Xu?) predictions on rates in B decays: neutral Z partner should exist M~ M(Z+(4430))+few MeV decay modes: Ψ’π0,Ψ’η or ηc(2S)ρ0, ηc(2S)ω charged partner for X(3872)/X(3875) M~3880MeV, decay modes: J/Ψπ+ or ηc(1S)ρ+ Jolanta Brodzicka Z(4430) and related KEK 20/11/200714

  15. Summary Z+(4430)→ψ’π+ observed in B→ψ’π+K by Belle First candidate for charged charmonium-like state. It is exotic! Tetraquark interpretation favored X(3872) →J/ψπ+π- ,DD* in B decays studied Recent results disfavor models that predict different properties between B+→XK+ and B0→XK0 Jolanta Brodzicka Z(4430) and related KEK 20/11/200715

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